1. Field of the Invention
The present invention relates to a step apparatus for heavy construction equipment and tree harvester having a leveling system, and more particularly to a step apparatus for heavy construction equipment and tree harvester having an improved leveling system, which can prevent a collision with an external obstacle or a lower driving structure by making the step apparatus in a step protector drawn out and seated in foldable steps even if an upper swing structure is tilted in an inclined workplace or is in a tilted state against the lower driving structure through operation of the leveling system.
2. Description of the Prior Art
Conventionally, heavy construction equipment and tree harvester having a leveling system, e.g. an excavator and tree harvester having a leveling system, can safely perform logging works or engineering works in a workplace having severe inclination or on the inclined ground, such as a slop, a hill, and the like.
If an upper frame including a cab and a working device is tilted at a specified angle due to the inclination of the workplace, a leveling system lifts up or pulls one lower side of the upper frame to offset the inclination, and thus the cab and the upper frame is kept roughly in a parallel state to a horizontal surface.
According to the heavy construction equipment and tree harvester having a leveling system as described above, since the height of structures mounted on the upper frame, such as the cab, engine room, and the like, is relatively high, the operator's approach to such structure for getting on or off the equipment is lowered, and the maintenance and repair work becomes difficult.
In consideration of the above-described drawbacks, a fixed step apparatus having foot steps or a step plate provided on one side of the upper frame to form stairs for getting on or off the equipment, has been widely used.
The conventional fixed step apparatus is a kind of step structure in which the step frame and foot steps hang down from one side of the upper frame, and are in a standing posture toward the lower driving structure or the upper swing structure.
Accordingly, the conventional fixed step apparatus is always in an exposed state as a step structure, without being affected by the change of the operation position of a safety lever typically installed in the cab, and thus an operator can keep the approach to various structures mounted on the upper swing structure, such as the cab, engine room, and the like.
FIG. 1 is a perspective view illustrating the use state of a conventional fixed step apparatus installed in heavy construction equipment and tree harvester having a leveling system, and FIG. 2 is a schematic perspective view of a conventional fixed step apparatus.
According to the heavy construction equipment and tree harvester having a leveling system as illustrated in FIG. 1, a leveling device 14 is installed between an upper frame 1 and a lower driving structure 2, and a cab 9, a boom 12 having a working device 13 such as a logging device or a bucket, and an engine room 11 are installed on an upper part of the upper frame 1. Also, in order for an operator to approach the cab 9, a step apparatus 10 is fixed to one side surface of the upper frame 1.
The conventional fixed step apparatus 10, as illustrated in FIG. 2, has a structure in which a stopper unit 3 is provided on one side of the upper frame 1, and a step frame hanger 6 having foot steps 5 hangs on the stopper unit 3.
Also, pinholes 4 for fixing the position of the step frame are formed on the step frame hanger 6. In the case of selectively fixing the step frame 7 in a standing posture so that the step frame 7 is headed upward from the upper part of the upper frame 1, stoppers 8 of the stopper unit 3 are inserted into the pinholes 4 of the step frame hanger 6, and thus the step frame 7 on the upper part of the upper frame 1 is kept in a standing posture.
Typically, in the case where the equipment such as an excavator having a leveling system performs work in an inclined area, the upper frame 1 is kept in a horizontal state that substantially corresponds to a horizontal surface H for prevention of overturn and work safety of the equipment, while the lower driving structure 2 is in an inclined state.
Also, the step apparatus 10 is fixed to be exposed from the upper frame 1, and if it is intended to adjust the exposed state of the step apparatus 10, the fixing position of the step frame 7 should be adjusted in a state where a safety lever is set to an operation mode.
However, the conventional step apparatus has the problem that, although the fixing position of the step frame 7 is adjusted, the step apparatus 10 is still exposed to an outside, and thus interference or collision may occur between the step apparatus and an external object or the lower driving structure.
For example, the conventional fixed step apparatus has severe problem that, when the upper swing structure and the upper frame are inclined or tilted at a preset angle due to an inclined ground surface, the step frame is projected toward the lower driving structure, and thus collision occurs between one side of the step frame and the lower driving structure to cause damage of the step frame and the lower driving structure.
Also, even in the case where the conventional step apparatus is fixed to the upper part of the upper frame in a standing posture by the stoppers to prevent collision between the step frame and the lower driving structure, collision may still occur between the step frame and an external object during working of the equipment.
The conventional fixed step apparatus also has severe problems that, in the case of adjusting the setting position of the step apparatus before leveling control of the upper frame or during working of the equipment, an operator should manually adjust the positions of the step frame and the steps up and down in a state where the operator directly hangs on the upper frame, and thus the manipulation performance is lowered with the operator's safety threatened.